The DPP noted that the threshold for criminality would be high in such a case.

He said: "The importance of free speech has to be recognised and our discretion applied."

He added: "I understand anxiety of Twitter community. Free speech is very important and the threshold for criminality must be high".

A spokesperson for the CPS confirmed that having a disclaimer in your Twitter biography that states that retweets are not endorsements does not offer any legal protection.

In 2010, Paul Chambers was arrested for tweeting: ""Crap! Robin Hood airport is closed. You've got a week and a bit to get your shit together otherwise I'm blowing the airport sky high!"

Chambers was found guilty at Doncaster magistrates court, and went on to lose his first appeal and a High Court appeal, before a second High Court appeal finally saw his conviction quashed on July 27 2012.

Chambers' tweet was retweeted thousands of times by sympathisers, who would theoretically be liable for prosecution had the police chosen to intervene.